Ultraviolet ray lamp



JV. F. HENDRY ULTRAVIOLET RAY LAMP May 2, 1933.

Filed Aug. 17, 1927 OR 5 y 5Y4 flQATTORNEY INVENT ofa mercury vapor lamp for 7 that in order to pass an wire from da Patented May 2, 1933 UN'ITEDSTATES PATENT OFFICE F. EEI'DBY. OF OSSWG, NEW YORK, ASSIGNOB, BY MESNE ASSIGNMENTS, TO munu'r'rnr ELECTRICAL SUPPLY COMPANY, INC, OFJEBSEY CITY, NEW JER- SKY, 1 GORPORA'IION 9F NEW JERSEY ULTRAVIOLET BAY LAMP Application flied-August 17, 1927. Serial No. 213,592.

This invention relates to devices for producing ultraviolet waves and relates more articularly to mercury vapor therapeutic amps.

An object of the invention is the provision producing ultraviolet rays, which is capab e of being ,op-

erated at high current density over along period of time.

Another object is the provision of an envelope of Pyrex glass having a copper wire hermetically sealed thereto.

Heretofore it has been fonnd diflicult to construct an ultraviolet ray lamp from borosilicate glass, such as Pyrex, for the reason large amount of ultraviolet rays through t e walls of a Pyrex glass lamp of the mercury type, it is necessary to run the lam. at high current density. This running 0 the lamp at high current density results in the heating of the envelope and electrodes to such a high temperature that extreme precautions are necessary in order to protect the seal of the leading-in In spite of the precautions taken to prevent overheating of the seal and leading in wire difficulty has been found in keeping the seal air tight and preventing leakage therethrough. A .copper wire cannot be sealed directly to Pyrex glass for the reason that Pyrex melts at a higher temperature than cop r and for this same reason many otherv or 'nary wires cannot be sealed to Pyrex. e

I have succeeded in obtaining a hermetic seal between Pyrex and a copper lead in wire by providing a cooling means for the lass in the neighborhood of the seal, placing tweenthe Pyrex and copper wire an insert of glass having alowermelting point than copper and by making the union between the last mentioned glam and the copper airtight throu h the use of balsam of fir.

These an other objects and advantages of the invention and the manner of obtaining them will be more clearly understood by reference to the following description and accompanying drawing.

In the drawing,'Fig.. 1 illustrates. a tube for producing ultra-violet light, constructed in accordance with my invention. Figs. 2 and=3 illustrate modifications of the tube shown in Fig. 1.

In Fig. 1, reference numeral 1 indicates the tube envelope of boro-silicate glass, such as Pyrex, which has two elongated portions 2 and 3, containing the electrode structures. The electrode structures consist of an electrode 4 which may be constructed of copper, carbon or other electrode material. This electrode comprises an elongated rod having a collar 5 around it at a point near one end and a longitudinal perforation, in the operating end thereof. The rod 4: is surrounded at its operating end by a sleeve 7, of insulating material, such as lava or the like. This sleeve 7 has a groove cuttherein, within which groove the collar 5 of the electrode 4 fits. The sleeve 7 entirely surrounds the ,end of the electrode 4 but does not touch the same, being spaced therefrom a small distance. Integral with the sleeve 7 is a flange 8 which serves to space the sleeve and electrode structure from the wall of the elongated portion of the envelope 2 and to prevent the discharge from passing down around the outside of the shield. This flange should be spaced from the tube wall slightly to allow for expansion. Packed around the entire electrode structure back of the flange on the insulating sleeve is ture. The electrode structure as described 7 forms a portion of the subject matter of my copending application Serial No. 180,788,

filed April 4, 1927, and the operation of the electrodes in this device is substantially the same as disclosed in said application. Current is conducted to the electrode from the outside of the tube by means of a copper wire 10. This wire 10 passes through and is sealed to a plug of glass 11, which is in turn welded within a drawn down tubular portion 12 of the Pyrex glass envelope. In order to provide an air-tight oint between the glass envelope and the wire end connecting to the drawn down portion 12 of the glass, envelope 1 is slightly flared out at 13 inorder to provide a reservoir for a quantity of balsam of fir 15, which is held within the reservoir by a lug 14 of wood or other'material thru which plug, wire 10 passes. The balsam of fir sticks to the wire and glass and thereby prevents any leakage of air to the inside of the receptacle. A sufiiciently lar e amount of the balsam is put in the receptac e to maintain a quantity of liquid balsam around the wire or a long period of time in spite of evaporation or solidification of some of the balsam. The glass wool 9 serves to conduct heat away from the electrode structure to the atmosphere before that heat reaches the seal of the leadin in wire. Likewise, the reduction in the iameter of the extension 2 of the glass envelope tends to reduce the amount of heat which can be transmitted to the seal. The additional fact that the glass at the sealing point between the leading in wire 10 and the envelope 12 has a relatively small volume with respect to its heat radiating area results in the additional cooling of the seal. The main result of all these features is to keep the tempera ture of the balsam of fir so low that the balsam does not solidify and thus lose its sealing qualities. These features are important as the balsam serves as an eflicien't sealing agent only when it is in the liquid state. As an additional precaution against heating of the seal, it might in some cases be desirable to provide an open ace between the body of glass wool and the eading in wire seal, the space being evacuated would serve as an effective heat insulator and revent any appreciable amount of heat rom being conducted from the electrode structure to the seal. The entire envelope is exhausted in such a manner that the glass wool and electrode structure is entirely free of air or any other deleterious gases and a small quantity of metallic mercury is deposited within the tube. A tube constructed in accordance with the foregoing description is capable of carryin current of high density and thereby p ucinf a maximum output of ultraviolet rays or therapeutical purposes, due to the fact that the particular electrode structure provides an eflicient cooling arrangement which permits the tube to be run at extremely high current density without destructive disintegration of the electrodes and without softening of the glass structure of the tube, allowing the Pyrex glass to as that rtion of the ultraviolet rays whic is benelitial to thehuman body.

While I have mentioned particularly that copper wire can be sealed to boro-sihcate glass, such as Pyrex, this type of seal is also useful in joining other kinds of wire to Pyrex or in joini different kinds of wire to quartz or to 0t er kinds of glass. The

above described seal is preferabl constructed by drawin down a portion 0 the tubular extension of t e envelope 1 and placing within this drawn down portion of the envelope a copper leadin in wire 10, which has 'oined thereto a head of glass such as that own as 702P and manufactured by the Corning Glass Works. The drawn down portion of the extension of the envelo 1 1s thereupon heated to a suficiently temperature to permit a further drawing down of the diameter thereof. This further drawing down causes the Pyrex wall to contact with the lass bead around the wire 10 and melt it. e drawing down is continued still further which results in the glass bead being elongated in the form of a pl as shown at 11 in Fig. 1 of the drawing.l e heat necessary to soften the wall of t e Pyrex envelope and melt the glass head around the wire 10 has to pass through a layer of Pyrex and a layer 0 702P glass before it affects the wire 10. This prevents the wire from attaining a suflicientliyl high temperature to melt it. While I ave found that 702P glass is a particularly advantageous glass to use, other glasses might be used as well, the main requisites being that the glass used for the plug have a lower melti temperature than the leading in wire an that it form a joint with tlie Pyrex envelope which will not crack upon a change in temerature. The seal is made air-tight, not

y its own construction of lass and but by the balsam of fir whic is mainta i nzl in the reservoir at the end of the drawn down portion of the envelope.

While I have mentioned that this of seal is particularly adaptable to cop r wire to a Pyrex envelope it is to be un erstood that other wires may be sealed to quartz or other kinds of glass than borosilicate glass, according to my invention.

It is desirable to use bore-silicate glam, such as Pyrex for an envelope of the ultraviolet ray lamp for the reason that glass will not pass ultra violet rays suflicienty and furthermore will not stand the high temperature at which it is desirable to operate this type of lamp. 1 have also found that Pyrex is particularly desirable for use as a violet ray lamp for therapeutical purposes as Pyrex p only that portion of the s trum which is beneficial to the human y.

The modifications shown in Figs. 2 and 3 illustrate other forms which my tube may take, and differ from the tube shown in Fig. 1 merely by the particular shape of the envelope and the relative position of the electrodes It will be obvious to those'skilled in the art that'the invention is capable of a variety of modifications and adaptations and that the present disclosure is intended merely to claims.

illustrate its nature without limiting its scope which is defined in the following What I claim is:

1. A high power ultraviolet ray lamp comprising a boro-silicate glass envelope containing a quantity of mercury and a pair of electrode structures, .each of said structures comprising a conducting rod having a cavity in the operating end thereof, a sleeve of insulating material surrounding said rod and spaced therefrom but a slight distance and a packing of glass wool around said electrode structure between the conducting rod and the glass envelope.

2. In a hermetic seal between a glass and a wire having a diflerent coeflicient of expansion than said glass, an elongated tube of said glass having welded therein a plug said plug, the end of sai of lass having a lower melting point than sai wire, said wire bein sealed through tube exposed to the atmosphere containinga quantity of balsam of fir.

3. A device for producing ultraviolet rays, comprising a boro-silicate glass tube having a pair of elongated extensions, an electrode positioned in each'of said extensions, an insulating sleeve surrounding each of said electrodes but spaced a slight distance therefrom, a packing of glass wool between said electrodes andthe walls of said extensions and a quantity of mercury within the said tube.

4. In an ultraviolet ray device, an envelope of boro-silicate glass having a tubular extension, a plug of 702P Corning glass positioned within said extension and welded thereto a copper wire sealed through said plug, and a quantity of balsam of fir in the end of the tubular extension."

5. In a hermetic seal, a boro-silicate glass tube containing a filling of 702P Corning glass and having a lead-in wire sealed through said filling, and a quantity of balsam of fir positioned around the atmosphere end of saidwire, and said glass filling.

i 6. In a seal between a copper wire and a tube of boro-silicate glass operating at high temperature, an elongated tubular portion attached to said envelope, said tubular portion having a further reduction in sizeforming a tube, said wire being maintained in position in said tube by means of a plug of glass having a lower melting temperature than copper sealed between the wire and the boro-sillcate glass tube, said seal being rendered airtight by means of a quantity of balsam of fir positioned in said tube and said wire.

7. In an ultra-violet ray lam for operating at high temperature, a boro-si icate glass envelope, an extension within said envelope, an electrode positioned in said extension, means for conducting heatfrom said electrode, a

copper wire seated within said extension and a quantity of balsam of fir placed in said extension around said wire.

8. In an electrical discharge device for operating at high temperature, a tube of glass having a relatively high melting point, said tube having an elongated tubular extension, an electrode positioned within saidiextension, a filling of heat conducting material between said electrode and the wall of said extension, a relatively low melting oint lead-in wire for said device said wire ing secured in a reduced portion of said extension by means of a glass of relatively low melting point, a quantity of balsam of fir in the outer end of said reduced portion around said wire and means for holding said balsam in position.

9. In a hermetic seal for a lead-in wire for a glass container, a wire sealed through the" wall of .said container and means for holding a quantity of balsam of fir around said wire at the said glass.

10.- In a hermetic seal for a lead-in wire.

in said extension, a packing of fibrous heat-- conducting material interposed between said electrode and said envelope within the extension thereof, a wirehaving a lowermelting point and a difierent co-eflicient of expansion than said-boro-silicate glass sealed within said extension and connected to said electrode, and a quantity of viscous sealing material disposed within said extension about said wire. 7

In testimony whereof, I have signed my name to this specification, this 16th day of August, 1927.

WILLIAM F. HENDRY.

point of its junction with the 4 

